If you decide to forfeit a starship with other cards deployed on it, yes, you can count the forfeit value of those cards.

Normally, you won't do this. You'll want to forfeit the cards on the ship first. But this could be advantageous if, for example, you have two pilots on one ship who just initiated a battle, and forfeiting only one of them would satisfy your attrition, but leave you with a lone pilot who could be beaten down on your opponent's next turn. Instead of forfeiting the one pilot, you could forfeit the ship as a single action, and the pilots would go with it.

Actually, Artie, if you forfeit the Falcon with say Han and Chewie aboard, Han's and Chewie's forfeit values will not count. You'd have to forfeit Han and Chewie individually if you want their forfeits to count.

In relation to an earlier question, there is one other case when you may want to forfeit a ship first. There is a Dark Side effect from Virtual Set 3, Besieged(V) that allows the capture of pilots/unpiloted ships that are forfeited. Here is it's game text:

Deploy on table. Whenever opponent forfeits a character or unpiloted starship at same system or sector as your Imperial capital starship, you may draw destiny. If destiny > target's destiny number, you may capture that character or starship. (Immune to Alter.)

At any time (except during battle), target any or all of your characters at one site to 'transport' (relocate) to any one other site. Draw destiny. Use that much Force to 'transport,' or place Interrupt in Lost Pile.

You can play it, however, when you think he's finished with his deploy phase actions. Just be careful, though. If you both pass on actions consecutively, you've lost your chance to use Elis, and it will go on to the next phase, where the player whose turn it is will get the first opportunity for an action.

Let's say i need a certain amount of force to use an interrupt. To get that force i use imperial supply tro gain 4 force, than can i use that next interrupt right after i use imperial supply to gain the force?

Battles shouldn't be confusing. During the weapons segments, you trade opportunities for actions until both players pass consecutively.

Let's say Dark side initiates battle. He gets the first opportunity for an action, so he fires a blaster at, say Han. That goes through the normal procedure as described on the weapon, and it has the appropriate results.

Next, Light side gets to play an action if they wish. They can do anything they are legally able to do during the weapons segment, be it fire a weapon, use game text on a character, or play an Interrupt.

After that, the opportunity passes back to the dark side player, and so on until both players do not wish to perform weapons segment actions.

I think what he's asking is if you play an interrupt, does it count as if you've fired a weapon? So DS player fires a weapon, LS player uses an interrupt, DS player fires another weapon. I think the same also goes for using the game text of a character in that you lose your weapon phase. Not sure though.